532
AXNT20 KNHC 200536
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
136 AM EDT THU SEP 20 2018
TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA, CENTRAL AMERICA
GULF OF MEXICO, CARIBBEAN SEA, NORTHERN SECTIONS OF SOUTH
AMERICA, AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY, WEATHER OBSERVATIONS, RADAR AND METEOROLOGICAL ANALYSIS.
BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0500 UTC.
..TROPICAL WAVES
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 21W/23W FROM 20N
SOUTHWARD. THIS WAVE IS ASSOCIATED WITH A DISTINCT 700 MB TROUGH.
ISOLATED MODERATE RAINSHOWERS ARE FROM 10N TO 20N BETWEEN AFRICA
AND 23W.
AN ATLANTIC OCEAN SURFACE TROUGH IS ALONG 19N29W 10N31W.
RAINSHOWERS ARE POSSIBLE WITHIN 360 NM TO THE EAST OF THE TROUGH,
AND WITHIN 300 NM OF THE WESTERN SIDE OF THE TROUGH. THE TROUGH
IS ASSOCIATED WITH A DISTINCT 700 MB TROUGH.
AN ATLANTIC OCEAN SURFACE TROUGH IS ALONG 46W/48W, FROM 05N TO
13N. SCATTERED TO NUMEROUS STRONG RAINSHOWERS ARE FROM 09N TO 11N
BETWEEN 46W AND 48W.
A CARIBBEAN SEA TROPICAL WAVE IS ALONG 66W/67W FROM 20N
SOUTHWARD, MOVING ACROSS THE WESTERN PART OF PUERTO RICO.
WIDELY SCATTERED MODERATE TO ISOLATED STRONG RAINSHOWERS ARE FROM
20N SOUTHWARD BETWEEN 62W AND 70W. A LARGE AREA OF SAL FOLLOWS
THIS WAVE, FROM THE LEEWARD ISLANDS TO 50W. THIS AREA EVENTUALLY
WILL SPREAD WESTWARD, ACROSS THE EASTERN CARIBBEAN SEA ISLANDS,
BRINGING HAZY SKIES AND STABLE CONDITIONS.
..MONSOON TROUGH/ITCZ
THE MONSOON TROUGH PASSES THROUGH THE COASTAL SECTIONS OF SENEGAL
NEAR 13N17W TO 12N21W. THE ITCZ EXTENDS FROM 10N24W TO 08N33W TO
06N44W. WIDELY SCATTERED MODERATE TO ISOLATED STRONG RAINSHOWERS
ARE FROM 04N TO 13N BETWEEN 16W AND 60W.
..DISCUSSION
GULF OF MEXICO...
UPPER LEVEL CYCLONIC WIND FLOW COVERS FLORIDA AND THE NE CORNER OF
THE GULF OF MEXICO. EARLIER WIDELY SCATTERED MODERATE RAINSHOWERS
THAT WERE INLAND, HAVE WEAKENED AND DISSIPATED.
AN UPPER LEVEL TROUGH IS IN MEXICO AND SOUTH TEXAS. MIDDLE LEVEL
AND UPPER LEVEL CLOUDS ARE OFF THE COAST FROM NE MEXICO TO SOUTH
TEXAS.
A SURFACE TROUGH, THE REMNANT OF ISAAC, IS IN THE EASTERN PART OF
THE YUCATAN PENINSULA. EARLIER SCATTERED TO NUMEROUS STRONG
RAINSHOWERS, THAT WERE IN THE WESTERN SECTIONS OF THE YUCATAN
PENINSULA, HAVE WEAKENED AND DISSIPATED, AND MOVED OFFSHORE.
ISOLATED MODERATE TO LOCALLY STRONG RAINSHOWERS ARE IN THE ISTHMUS
OF TEHUANTEPEC OF SOUTHERN MEXICO AND NEIGHBORING WATERS, FROM
21N SOUTHWARD BETWEEN LAND AND 94W.
HIGH PRESSURE WILL BUILD ACROSS THE EASTERN U.S.A. THROUGH
TONIGHT. THIS WILL ALLOW GENTLE TO MODERATE E TO SE BREEZES AND 2
TO 4 FT SEAS ACROSS THE GULF OF MEXICO THROUGH SUNDAY. A SURFACE
TROUGH, THAT IS IN THE NW CARIBBEAN SEA AND THE YUCATAN CHANNEL,
WILL SHIFT WESTWARD ACROSS THE SOUTH CENTRAL GULF OF MEXICO AND
THE YUCATAN PENINSULA THROUGH TONIGHT, AND ACROSS THE SOUTHWEST
GULF OF MEXICO ON THURSDAY AND FRIDAY, BEFORE DISSIPATING SAT.
CARIBBEAN SEA...
AN UPPER LEVEL TROUGH PASSES THROUGH THE ATLANTIC OCEAN, THROUGH
THE WINDWARD PASSAGE, INTO THE SW CORNER OF THE CARIBBEAN SEA
NEAR THE COASTS OF COSTA RICA AND PANAMA. ISOLATED MODERATE TO
LOCALLY STRONG RAINSHOWERS ARE FROM 16N SOUTHWARD FROM 79W
WESTWARD. RAINSHOWERS ARE POSSIBLE FROM 16N NORTHWARD FROM 79W
WESTWARD.
AN EASTERN CARIBBEAN SEA TROPICAL WAVE, ALONG 67W, WILL MOVE
WESTWARD, ACROSS THE CENTRAL CARIBBEAN SEA FROM THURSDAY INTO
FRIDAY. THE WAVE WILL PASS TO THE WEST OF THE AREA THROUGH LATE
SATURDAY INTO SUNDAY. STRONG GUSTS ARE POSSIBLE NEAR RAINSHOWERS,
THAT ARE ASSOCIATED WITH THIS TROPICAL WAVE NEAR THE LESSER
ANTILLES AND EASTERN CARIBBEAN SEA THROUGH THIS EVENING. HIGH
PRESSURE BUILDING FROM THE CENTRAL ATLANTIC OCEAN INTO THE CENTRAL
BAHAMAS WILL SUPPORT MODERATE TO FRESH TRADE WINDS AND BUILDING
SEAS ACROSS THE ENTIRE BASIN FROM LATE ON WEDNESDAY THROUGH
FRIDAY.
ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS ABOUT 800 NM TO 850 NM TO THE ESE OF THE
COAST OF THE U.S.A. AN ASSOCIATED CYCLONIC CIRCULATION CENTER IS
ABOUT 130 NM TO THE ENE OF BERMUDA. 24-HOUR RAINFALL TOTALS THAT
ARE LISTED FOR THE PERIOD THAT ENDED AT 20/0000 UTC, ACCORDING TO
THE PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES,
MIATPTPAN/SXCA01 KNHC...ARE 2.20 IN BERMUDA. THE TROUGH EVENTUALLY
PASSES THROUGH THE WINDWARD PASSAGE, INTO THE SW CORNER OF THE
CARIBBEAN SEA NEAR THE COASTS OF COSTA RICA AND PANAMA. ISOLATED
TO WIDELY SCATTERED MODERATE AND LOCALLY STRONG RAINSHOWERS COVER
THE ATLANTIC OCEAN FROM 20N NORTHWARD BETWEEN 50W AND 65W.
A SECOND UPPER LEVEL TROUGH IS MOVING FROM THE U.S.A. MIDDLE
ATLANTIC STATES SOUTHEASTWARD. A COLD FRONT IS ABOUT 400 NM TO THE
EAST OF THE U.S.A. THE COLD FRONT PASSES THROUGH 32N72W TO
29N80W. ISOLATED MODERATE RAINSHOWERS COVER THE WATERS THAT ARE
FROM 29N NORTHWARD FROM 65W WESTWARD.
THE REMNANT LOW PRESSURE CENTER OF JOYCE IS A 1013 MB LOW PRESSURE
CENTER THAT IS NEAR 30N30W. RAINSHOWERS ARE POSSIBLE FROM 25N TO
32N BETWEEN 27W AND 38W, IN A SWIRL OF LOW LEVEL AND MIDDLE LEVEL
CLOUDS.
AN UPPER LEVEL TROUGH EXTENDS FROM A CYCLONIC CIRCULATION CENTER
THAT IS NEAR 33N23W, TO A SECOND CYCLONIC CIRCULATION CENTER THAT
IS NEAR 27N37W, TO A THIRD CYCLONIC CIRCULATION CENTER THAT IS
NEAR 15N52W, TO 12N59W. RAINSHOWERS ARE POSSIBLE FROM 20N BETWEEN
20W AND 50W.
A SURFACE TROUGH, REACHING FROM BERMUDA TO 27N74W, WILL SHIFT NW
AND DISSIPATE TONIGHT AS THE CENTRAL ATLANTIC OCEAN RIDGE BUILDS
INTO THE SOUTHERN BAHAMAS. LOW PRESSURE MOVING OFF THE CAROLINAS
TONIGHT WILL DRAG A WEAKENING FRONTAL BOUNDARY ACROSS THE WATERS
NORTH OF 27N ON THURSDAY AND FRIDAY. THE LOW WILL SINK TO NEAR
31N67W ON FRIDAY EVENING. IT WILL DRIFT W, AND SLOWLY WEAKEN ON
SATURDAY AND SUNDAY. NE SWELL WILL MOVE INTO THE OPEN WATERS EAST
OF THE BAHAMAS FROM FRIDAY THROUGH THE EARLY PARTS OF THE NEXT
WEEK.
FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE
MT
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